Effect of Heat Treatment on the Mechanical and Corrosion Properties of Mg-Zn-Ga Biodegradable Mg Alloys

Mg alloys have mechanical properties similar to those of human bones, and have been studied extensively because of their potential use in biodegradable medical implants. In this study, the influence of different heat treatment regimens on the microstructure and mechanical and corrosion properties of biodegradable Mg-Zn-Ga alloys was investigated, because Ga is effective in the treatment of disorders associated with accelerated bone loss. Solid-solution heat treatment (SSHT) enhanced the mechanical properties of these alloys, and a low corrosion rate in Hanks' solution was achieved because of the decrease in the cathodic-phase content after SSHT. Thus, the Mg-4 wt.% Zn-4 wt.% Ga-0.5 wt.% Y alloy after 18 h of SSHT at 350 degrees C (ultimate tensile strength: 207 MPa; yield strength: 97 MPa; elongation at fracture: 7.5%; corrosion rate: 0.27 mm/year) was recommended for low-loaded orthopedic implants.